The infrahyoid flap: A comprehensive review of an often overlooked reconstructive method.

The infrahyoid flap is a myocutaneous pedicled flap mainly nourished by the superior thyroid vessels through the perforators of theinfrahyoidmuscles. This thin and pliableflap provides a skin island of about 7 by 4cm from the central part of the anterior neck. Theflapcan be transferred on its pedicle of superior thyroid artery and vein to reconstruct medium sized head and neck defects created aftercancer ablation. We have successfully used this flap in a series of 40 cases with no total flap loss and with 1 case of superficial skin necrosis. The aim of this review is to highlight the clinical usefulness of this pedicled flap even in the microvascular free flap era. A comprehensive review of the available literature reporting on the infrahyoid flap has been carried out using a web search. The history of the infrahyoid flap, the surgical technique with technical innovations, the clinical utility and limitations of this flap, are reported and discussed. Among the 7 larger series (cohort larger than 50 cases) a total of 956 flaps were performed, and the global success rate was 91.7\%, with failures being mainly related to partial skin necrosis, as the rate of total (skin and muscle) flap necrosis was only 1\%. This flap is reliable, easy to harvest during neck dissection, oncologically safe, it does carry a negligible donor site morbidity. This paper highlights how the infrahyoid flap can represent an excellent reconstructive solution in selected patients and head and neck sites

Quasi-monoenergetic femtosecond photon sources from Thomson Scattering using laser plasma accelerators and plasma channels

Narrow bandwidth, high energy photon sources can be generated by Thomson scattering of laser light from energetic electrons, and detailed control of the interaction is needed to produce high quality sources. We present analytic calculations of the energy-angular spectra and photon yield that parametrize the influences of the electron and laser beam parameters to allow source design. These calculations, combined with numerical simulations, are applied to evaluate sources using conventional scattering in vacuum and methods for improving the source via laser waveguides or plasma channels. We show that the photon flux can be greatly increased by using a plasma channel to guide the laser during the interaction. Conversely, we show that to produce a given number of photons, the required laser energy can be reduced by an order of magnitude through the use of a plasma channel. In addition, we show that a plasma can be used as a compact beam dump, in which the electron beam is decelerated in a short distance, thereby greatly reducing radiation shielding. Realistic experimental errors such as transverse jitter are quantitatively shown to be tolerable. Examples of designs for sources capable of performing nuclear resonance fluorescence and photofission are provided

Laser-heater assisted plasma channel formation in capillary discharge waveguides

A method of creating plasma channels with controllable depth and transverse profile for the guiding of short, high power laser pulses for efficient electron acceleration is proposed. The plasma channel produced by the hydrogen-filled capillary discharge waveguide is modified by a ns-scale laser pulse, which heats the electrons near the capillary axis. This interaction creates a deeper plasma channel within the capillary discharge that evolves on a ns-time scale, allowing laser beams with smaller spot sizes than would otherwise be possible in the unmodified capillary discharge.Comment: 5 pages, 3 figure

A complementary compact laser based neutron source

Several experiments of neutron generation using high intensity laser sources, with a power exceeding 10^19W/cm^2 via TNSA (Target Normal Sheath Acceleration) or other similar methods, have been performed in the past years in different laboratories. However, so far there is no one running neutron source based on such a technology. In the framework of the Conceptual Report Design of a new accelerator in the Eupraxia project we are studying the possibility to have a laser-based neutron source, not only by TNSA but also from self-injection schemes. We focus our attention on the applications in cultural heritage studies as well also on the complementary role that such a source can have in the framework of large facilities devoted to radiation production.Comment: 4 pages, two figures, 3rd European Advanced Accelerators Concept

Infrahyoid fascio-myocutaneous flap as an alternative to free radial forearm flap in head and neck reconstruction.

The use of microvascular free flaps is currently the favored method for the reconstruction of defects after resection of head and neck cancer. The flap most commonly used for head and neck reconstruction is the free radial forearm flap, but the less popular infrahyoid flap represents a good alternative in selected cases. This flap has proven to be helpful in the reconstruction of a wide range of moderate-sized head and neck defects.We reviewed a series of 13 patients with defects resulting from cancer of the head and neck, who underwent infrahyoid flap reconstruction as an alternative to free radial forearm flap. The series includes 12 squamous cell carcinomas arising from the oral cavity and oropharynx, and 1 Merkel cell carcinoma of the submental skin. In the harvesting of the flap, the technical modifications recently suggested by Dolivet et al were used in all cases. Furthermore, another technical change has been introduced so creating a new infrahyoid facio-myocutaneous flap (IHFMCF). The surgical technique is described in detail.No total or partial flap necrosis was experienced. All reconstructions healed quickly without wound complications and with good functional results. The healing process in the donor site was excellent in every case with good aesthetic results.The IHFMCF is a versatile, reliable, and convenient flap suitable for repairing small and medium-sized defects of the oral cavity and oropharynx and obviates the need for a microvascular reconstruction

Effects of Hyperbolic Rotation in Minkowski Space on the Modeling of Plasma Accelerators in a Lorentz Boosted Frame

Laser driven plasma accelerators promise much shorter particle accelerators but their development requires detailed simulations that challenge or exceed current capabilities. We report the first direct simulations of stages up to 1 TeV from simulations using a Lorentz boosted calculation frame resulting in a million times speedup, thanks to a frame boost as high as gamma=1300. Effects of the hyperbolic rotation in Minkowski space resulting from the frame boost on the laser propagation in the plasma is shown to be key in the mitigation of a numerical instability that was limiting previous attempts